Effects of rare earth elements on telomerase activity and apoptosis of human peripheral blood mononuclear cells

To study the effects of rare earth exposure on human telomerase and apoptosis of mononuclear cells from human peripheral blood (PBMNCs). The blood contents of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, were measured by inductively coupled plasma-mass spectrometry. Telomeric repeat amplification protocol assay and flow cytometer analysis were carried out to analyze the telomerase activity and apoptosis of PBMNCs, respectively. The total content of rare earth elements in the blood showed significant differences between the exposed group and the control group. The rare earth exposure increased the telomerase activity and the percentages of cells in the S-phase and the G₂/M phase in PBMNCs, but it had no effect on the apoptotic rate of PBMNCs. Under the exposure to lower concentrations of rare earth elements, the telomerase activity of PBMNCs in the exposed group was higher than that of the control group, and there was no effect on the apoptotic rate of PBMNCs, but promoted the diploid DNA replication and increased the percentages of G₂/M- and S-phase cells.     

Localization of the actin-binding protein fesselin in chicken smooth muscle

This report compares cellular localization of fesselin in chicken smooth, skeletal and cardiac muscle tissues using affinity purified polyclonal fesselin antibodies. Western blot analyses revealed large amounts of fesselin in gizzard smooth muscle with lower amounts in skeletal and cardiac muscle. In gizzard, fesselin was detected by immunofluorescence as discrete cytoplasmic structures. Fesselin did not co-localize with talin, vinculin or caveolin indicating that fesselin is not associated with dense plaques or caveolar regions of the cell membrane. Immunoelectron microscopy established localization of fesselin within dense bodies. Since dense bodies function as anchorage points for actin and desmin in smooth muscle cells, fesselin may be involved in establishing cytoskeletal structure in this tissue. In skeletal muscle, fesselin was associated with desmin in regularly spaced bands distributed along the length of muscle fibers suggesting localization to the Z-line. Infrequently, this banding pattern was observed in heart tissue as well. Localization at the Z-line of skeletal and cardiac muscle suggests a role in contraction of these tissues.     

Novel Bacillus thuringiensis δ-endotoxin active against Locusta migratoria manilensis

A novel δ-endotoxin gene was cloned from a Bacillus thuringiensis strain with activity against Locusta migratoria manilensis by PCR-based genome walking. The sequence of the cry gene was 3,432 bp long, and it encoded a Cry protein of 1,144 amino acid residues with a molecular mass of 129,196.5 kDa, which exhibited 62% homology with Cry7Ba1 in the amino acid sequence. The δ-endotoxin with five conserved sequence blocks in the amino-terminal region was designated Cry7Ca1 (GenBank accession no. {"type":"entrez-nucleotide","attrs":{"text":"EF486523","term_id":"1121787749","term_text":"EF486523"}}EF486523). Protein structure analysis suggested that the activated toxin of Cry7Ca1 has three domains: 227 residues forming 7 α-helices (domain I); 213 residues forming three antiparallel β-sheets (domain II); and 134 residues forming a β-sandwich (domain III). The three domains, respectively, exhibited 47, 44, and 34% sequence identity with corresponding domains of known Cry toxins. SDS-PAGE and Western blot analysis showed that Cry7Ca1, encoded by the full-length open reading frame of the cry gene, the activated toxin 1, which included three domains but without the N-terminal 54 amino acid residues and the C terminus, and the activated toxin 2, which included three domains and N-terminal 54 amino acid residues but without the C terminus, could be expressed in Escherichia coli. Bioassay results indicated that the expressed proteins of Cry7Ca1 and the activated toxins (toxins 1 and 2) showed significant activity against 2nd instar locusts, and after 7 days of infection, the estimated 50% lethal concentrations (LC₅₀s) were 8.98 μg/ml for the expressed Cry7Ca1, 0.87 μg/ml for the activated toxin 1, and 4.43 μg/ml for the activated toxin 2. The δ-endotoxin also induced histopathological changes in midgut epithelial cells of adult L. migratoria manilensis.     

自旋捕捉结合液相色谱/电子自旋共振/质谱联用技术用于检测多不饱和脂肪酸过氧化过程中产生的自由基(英文)

ω-6和ω-3类多不饱和脂肪酸是两种人体所需的重要营养物质。人体内的很多生理病理过程均涉及到这些多不饱和脂肪酸,以及它们在环氧合酶(cyclooxygenase,COX)和脂氧合酶(lipoxygenase,LOX)催化下产生的过氧化代谢物。环氧合酶和脂氧合酶催化的多不饱和脂肪酸的过氧化是复杂的生化过程,会产生一系列的自由基产物。这些自由基产物又会与蛋白质、DNA和RNA结合,从而导致很多生理功能的改变。然而一直以来,缺乏合适的分析方法来有效分离和鉴定这些自由基产物,限制了人们对环氧合酶和脂氧合酶,以及多不饱和脂肪酸的过氧化在生理作用方面的研究。直到最近,才出现了对COX/LOX催化产生的活泼自由基定性和定量分析的报道。这里将对一种可以用来鉴定体外脂类过氧化产生的自由基产物的自旋捕捉-LC/ESR/MS联用技术的发展与改进过程进行综述。这种新颖的LC/ESR/MS联用技术首次使得直接检测多不饱和脂肪酸代谢产生的自由基成为可能,这对自由基的生理学作用研究是一个重大突破,为人们在多不饱和脂肪酸的生理作用以及环氧合酶和脂氧合酶催化的脂质过氧化方面的研究带来了极大便利。     

鸡马立克氏病病毒B抗原片段在大肠杆菌中表达

鸡马立克氏病病毒ＢａｍＨＩ基因文库Ｉ３质粒中含有编码Ｂ抗原膜外Ｄｏｍａｉｎ的ＤＮＡ序列。经ＳｃａＩ和ＳｐｈＩ双酶酶解Ｉ３质粒,分离获得７６４ｂｐＤＮＡ片段,并克隆进Ｍ１３ｍｐ１９中。ＤＮＡ序列测定分析表明克隆片段为ＭＤＶ－Ｂ抗原基因的４９４－１２５８ｂｐ部分序列。进一步分离ＮｃｏＩ－ＨｉｎｄＩＩＩ部分基因片（５３０ｂｐ）,克隆于ＰＬＰｒｏｍｏｔｅｒ控制下的含有修饰型ｃＩｔｓ８５７基因的表达载体中,     

CO_2倍增对植物生长和土壤微生物生物量碳、氮的影响

关于大气ＣＯ２浓度倍增（即为７００μｍｏｌＣＯ２·ｍｏｌ－１空气）将对植物生长产生诸多影响,已有大量报道［１,２］。但ＣＯ２倍增对植物及所在土壤中微生物影响的研究甚少［３,４］。土壤微生物是陆地生态系统中最活跃的成分,担负着分解动植物残体的重要作用,...     

用RAPD技术鉴定小麦属间不对称体细胞杂种

用随机引物扩增多态DNA(RAPD)技术对三种不同组合:小麦(Triticum aestivum)( )簇毛麦(Haynaldia villosa);小麦( )羊草(Leymus chinensis)和小麦( )高冰草(Agropyron elongatum)的属间不对称杂种进行分子鉴定,不同杂种植株的基因组经随机引物扩增后,均出现双亲的多态特异产物,证实它们含有双亲的基因组。将引物OPJ-12扩增的高冰草多态特异产物(分子量为0.77bp的DNA片段)分离纯化并标记作探针,用Southern杂交证明了小麦( )高冰草杂种经OPJ-12扩增的0.77kbp特异片段与高冰草这一片段具有同源性。本文结果证明,RAPD技术可作为小麦属间不对称体细胞杂种的一种快速、简便、有效的分子鉴定方法。     

瞬时受体电位香草酸亚型1激活释放的P物质在小鼠急性心肌梗死后凋亡中的保护作用

瞬时受体电位香草酸亚型1 (transient receptor potential vanilloid 1, TRPV1)在心肌缺血激活后可传导心绞痛信号和释放P物质(substance P, SP).SP是速激肽家族成员之一,主要通过结合并激活神经激肽1 (neurokinin 1,NK1)受体发挥作用. TRPV1和SP在缺血性心脏病中对心功能的恢复和重塑有一定保护作用,但对心肌梗死后凋亡的作用及具体机制尚不明确.本研究用TRPV1基因敲除(TRPV1-/- )小鼠和野生型(wide type, WT)小鼠建立心肌梗死模型,并外源性给予SP和NK1受体拮抗剂RP67580,用TTC染色法观察梗死的面积,TUNEL法检测心肌细胞凋亡指数,Western印迹方法检测caspase-3、Bcl-2、Bax、p53的蛋白表达.结果发现,心肌梗死24 h后,TRPV1-/-小鼠比WT小鼠梗死面积更大,凋亡指数和caspase-3活性更高,Bcl-2/Bax和p53蛋白表达更低. SP预处理可以明显缩小TRPV1-/-小鼠梗死面积,降低凋亡指数、caspase-3活性和升高Bcl-2/Bax比值,而在WT小鼠中改善不明显.外源性给予RP67580,阻断SP与NK1受体结合后,与相应对照组相比,WT小鼠梗死面积和凋亡指数更大,caspase-3蛋白表达更高,Bcl-2/Bax比值更低;TRPV1-/-小鼠与相应对照组比较,凋亡指数和caspase-3表达升高,Bcl-2/Bax比值降低.研究结果表明,SP可能介导了TRPV1在急性心肌梗死后凋亡中的保护作用.     

Identifying Hfq-binding small RNA targets in Escherichia coli

The Hfq-binding small RNAs (sRNAs) have recently drawn much attention as regulators of translation in Escherichia coli. We attempt to identify the targets of this class of sRNAs in genome scale and gain further insight into the complexity of translational regulation induced by Hfq-binding sRNAs. Using a new alignment algorithm, most known negatively regulated targets of Hfq-binding sRNAs were identified. The results also show several interesting aspects of the regulatory function of Hfq-binding sRNAs.